How Do I File Taxes for a Deceased Person in Connecticut?

Connecticut requires a final state income tax return for the decedent alongside the federal Form 1040; a federal estate tax return (Form 706) is required only for estates above $15,000,000.

State

Approximate Estate Value

Estate Earns Income

YesNo

Date of Death

Three returns are due.

IRS Form 1040, CT-1040 and CT-706/709.

Federal

Final income tax return

A final federal income tax return is required for income earned from January 1 through the date of death.

Form: IRS Form 1040
Due: April 15 following year of death

Write "DECEASED," the decedent's name, and the date of death across the top of the return. If filing jointly with a surviving spouse, include both incomes. Attach Form 1310 to claim a refund, unless you are the surviving spouse filing a joint return or a court-appointed personal representative attaching a copy of the court certificate to the original return.

IRS Form 1040 File online

Connecticut

Final income tax return

A final state return is required for income earned through the date of death.

Form: CT-1040
Due: April 15 following year of death

An executor, administrator, or surviving spouse files for the portion of the year before death. Check the box next to the deceased taxpayer's SSN on the front page of the return, sign for the deceased taxpayer on the signature line, and indicate the date of death.

CT-1040 File online

Estate tax return

Connecticut requires an estate tax return from every estate, regardless of size. The estate value ($0) is below the $15,000,000 threshold, so the return is filed but no state estate tax is typically due.

Form: CT-706/709
Due: 6 months after date of death
Extension: CT-706/709 EXT (up to 9 additional months)

Connecticut requires an estate tax return for every decedent who dies a resident (and for nonresidents owning CT real or tangible personal property) — § 12-392(b)(3)(J). The exemption decides only where it is filed.

CT-706/709

Tax clearance

Connecticut requires tax clearance before distribution

Estate tax lien (§ 12-398(d)) attaches to the decedent's CT real property from the due date until the tax is paid.

Form: CT-4422 UGE → CT-792 UGE (taxable estates); CT-706 NT (nontaxable estates, via Probate Court)

Connecticut tax clearance

Not required

Federal estate income tax return: IRS Form 1041 is only required if the estate earns $600 in gross income or more during administration.
Federal estate tax return: The estate value ($0) is below the federal exemption of $15,000,000. IRS Form 706 is generally not required.
Connecticut estate income tax return: A fiduciary return is only required if the estate earns income above the filing threshold (Required if federal Form 1041 is required or estate has any Connecticut taxable income).

General information about tax filing requirements after a death, not tax or legal advice. Consult a licensed tax professional for tax questions. Data verified Sep 15, 2026

Frequently Asked Questions

At minimum, a final federal income tax return (Form 1040) for income earned through the date of death, and Connecticut requires a final state income tax return (CT-1040) as well. If the estate earns income during administration, a federal fiduciary return (Form 1041) and a Connecticut fiduciary return (CT-1041) may also be required. Connecticut also requires a state estate tax return from every estate, regardless of size; the $15,000,000 threshold decides whether tax is due, not whether a return is filed.

The final federal income tax return is due April 15 following year of death. The final Connecticut return is due April 15 following year of death. The Connecticut fiduciary return is due April 15 (calendar year); extension via CT-1041 EXT. The Connecticut estate tax return (CT-706/709) is due 6 months after date of death.

Yes. Estate tax lien (§ 12-398(d)) attaches to the decedent's CT real property from the due date until the tax is paid. Distributing assets without the clearance can leave the executor or trustee personally liable.

Yes. Connecticut imposes a state estate tax on an estate above $15,000,000. It is separate from the federal estate tax. A state estate tax return is filed for every estate, regardless of size; below the threshold no tax is due, but the return is still required.

Yes. Estate size does not change the final income tax return: a final Form 1040 is filed whatever the estate is worth if the decedent had income. What a smaller estate avoids is the federal estate tax return (Form 706), due 9 months after date of death (6-month extension available) and required only above $15,000,000. Connecticut, however, requires its state estate tax return from every estate regardless of size: below $15,000,000 no state tax is due, but the return is still filed.

Tax Filing After Death in Connecticut

After a death in Connecticut, both federal and state tax returns must be filed. A final income tax return covers the deceased's income through the date of death, and a separate fiduciary return may be needed if the estate earns income during administration. A federal estate tax return (Form 706) is required only for estates above the federal exemption of $15,000,000.

Connecticut imposes a state estate tax on taxable estates exceeding $15,000,000, and requires an estate tax return from every estate regardless of size — smaller estates file the return even though no tax is due. The Connecticut death tax calculator estimates the liability.

Filing deadlines depend on the type of return. The final Connecticut income tax return is due April 15 following year of death. The state estate tax return (CT-706/709) is due 6 months after date of death. The Connecticut estate settlement plan tracks all deadlines in order.

SimplyTrust Editorial·Updated September 20, 2026

Legal Sources

26 USC 2001(c), 2010; P.L. 119-21 §70106
26 USC 6012(b)(1)
26 USC 6018; 26 USC 6075(a)
Conn. Gen. Stat. § 12-391
Conn. Gen. Stat. § 12-700
Conn. Gen. Stat. §§ 12-391, 12-392, 12-398, 12-642

Data sourced from Connecticut statutes and official state code. How we research.

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